Since the 18th century, chlorine-based disinfectants have been employed in medical applications for their rapid, potent and broad-spectrum bactericidal activity. For example, Dakin developed a chlorine solution which subsequently proved useful for lavaging foul wounds. See H. D. Dakin, Brit. Med. J., ii:809 (December 1915). Chlorine Has also been widely used as a germicide in water and sewage Treatment.
Among the useful chlorine-based disinfectants are alkali metal and alkaline earth metal hypochlorites. Sodium, potassium, lithium and calcium hypochlorites are known for their disinfecting and bleaching properties. See e.g., U.S. Pat. No. 3,717,580 to Echols et al.
Despite the long history of efficacious use of chlorine-based disinfectants, few chlorine compounds are used today as sterilants in medical and dental practice. The many problems associated with chlorine-based disinfectants limit their usefulness for disinfecting or sterilizing instruments or hard surfaces. For example, the instability of the active ingredient causes the effectiveness of some hypochlorite disinfectant solutions to deteriorate significantly within a few hours of preparation.
An even more significant problem associated with use of chlorine-based disinfectants, however, is the highly corrosive nature of these solutions due to high oxidation potential. For example, concentrations of hypochlorous acid sufficient to sterilize standard bacteriological challenges also quickly attack metals, even stainless steel, causing discoloration and pitting. Metal instruments soaked in chlorine solutions tend to be irreversibly damaged; sharp edges are destroyed and metal surfaces are pitted and darkened.
As a result, corrosion inhibitors have been recommended for use with hypochlorites. See, e.g., G. H. Botham et al., "Corrosion by Commercial Sodium Hypochlorite and its Inhibition," J. Dairy Res, vol. 16, 37 (1949). The use of corrosion inhibitors, however, has been plagued with problems, such as the reactivity of many inhibitors with chlorine and the resulting deactivation of the disinfectant solution.
Accordingly, there is a great need in the medical and dental arts for a disinfectant which will allow the rapid and effective sterilization of medical and dental instruments and hard surfaces at room temperature without corrosive effects and which exhibits sufficient chemical stability.